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Roots and Shoots

Kaya, Kiana, and Kalea model how a plant’s roots, stems, and leaves take up and store water from the environment, in this video from PLUM LANDING. Using sponges, waxed paper, and water, they compare how different characteristics, such as leaf thickness and a protective waxy coating, help plants store water and keep from drying out.

Understand that all living things need water to survive. The absence or presence of water in an ecosystem determines what can live there.

Understand that plants’ parts, including roots, stems, leaves, flowers, and fruit, help them to survive and to grow.

Build a model that represents how a plant takes in and stores water.

Suggested Time: 60 minutes

Materials

For each pair of students:

2 dinner-sized plates, paper or plastic

1 kitchen sponge, approximately 3.5 x 6 x 1"

2 pieces of paper toweling or colored construction paper

4 pieces of waxed paper, approximately 8 x 11"

Paper or plastic cups or other small containers

Scissors

String

Stapler

Water

Field notebooks and pencils

A potted houseplant or herb, or a dandelion or other small plant with its roots intact (only one for the class to look at as a group)

A water bottle or cup of water (for you to drink)

Before the Activity

Watch the video, read through the activity, and either build your own model plants (to show to students after you explain the activity) or draw a few sketches of what you would build.

(Optional) Cut the sponges and paper towels roughly into the shapes of plant parts, such as stems and leaves (sponges may be difficult for younger students to cut).

If you have a houseplant, especially a succulent such as a jade, aloe, or cactus, take it to your school.

(Optional) The night before you lead this activity, get a thin, soft leaf (a basil leaf, a piece of lettuce, a leaf plucked from a dandelion) and let it sit out overnight. Do the same with a leaf from a jade or aloe plant or an artichoke leaf. Take them with you to school for observation.

Warm-up: [Note: If you have already completed the “Viewing the Video” discussion in Teaching Tips, skip ahead to Part A of the main activity.] Introduce the topic of how plants meet their need for water by comparing plants to people. Take a big, noisy gulp of water. Be dramatic about it—say, "Ahhhh, that was refreshing!"

Ask:

What did I just do?

Why do you think I did that?

Then, hold up the plant for all the students to see.

Ask:

What does this plant do when it gets thirsty? Can it pour itself a cup of water?

How does this plant get the water it needs? It takes in water through its roots. This water travels through the rest of the plant.

What covering does the outside of your body have? Skin. Explain that one of the many things your skin does for you is to keep your body from drying out. Tell students that plants also have a special coating that keeps them from drying out. It is called the cuticle and is made of a waxy material.

(Optional) If you brought in a plant, give students the chance to gently touch it. Break an aloe or jade leaf in half, if you have one, so students can see and feel the inside. If you brought samples of leaves left out overnight, pass them around for everyone to see. Talk about how the thin leaf changed overnight as compared to a thick leaf.

Part A: Show and Tell

1. Show students the materials.

Ask:

How could we use these materials to build model plants that take up and store water? You might demonstrate for students how sponges and paper soak up water, and how drops of water bead up and roll off a sheet of waxed paper.

Which will hold water longer: plants with thick leaves and stems, or plants with thin leaves and stems? How could we find out?

How could we use the waxed paper to show how a wax coating helps keep plants from drying out?

2. Show students your sketches or the models you built, but emphasize that their plants should be their own creations—they do not need to copy what you did.

Part B: Brainstorm and Build!

1. Divide students into pairs to build two model plants. Their goal is to compare how just one feature—either a waxy coating or leaf and stem thickness—affects how well a plant takes up water and keeps from drying out. To best see how this one factor affects their model, it should be the only thing that's different between the two plants. This presents students an opportunity to practice designing experiments and testing variables. Have student pairs select which feature they want to test, or assign features to the pairs.

2. Give student pairs two minutes to talk with each other about how they will build their two model plants. Circulate among the group while students sketch their ideas in their notebooks.

Ask:

How will you make leaves? Stems? Roots?

How could you use the waxed paper?

3. Hand out materials and give students about 15 minutes to build their models. Remind students to think about how their model will represent roots (the parts of a plant that take up water from the soil) and to not wrap that part completely in waxed paper. Glue and tape will not hold together in water; have students use string and staples to fasten the parts of their creations.

4. Ask students to share their models with the class and predict what will happen when you pour water in the model plant's environment.

Ask:

What will happen if we pour water onto the plants?

What might happen to the water in the plants if we let them sit out overnight?

Part C: Let It Rain

1. Stand the model plants on a plate.

2. Pour about 1/4 cup of water on the plate, taking care to not pour it directly on the plants. Watch the water. Where does it go?

3. Remove the model plants from the wet plate and place them on a dry plate or on a countertop where they won't be disturbed.

Wrap-up Ask for a few volunteers to show what their model plants look like now and to predict how they will change over a few hours or overnight. Have students jot down their predictions in their field notebooks, using full sentences.

Ask:

How will the plants change over the next few hours or overnight?

What do you expect to see tomorrow?

How are these model plants similar to real plants? How are real plants different from these model plants?

If you are able to reconvene the group a few hours later or the next day, have a quick look at everyone's models. (Otherwise, have students take their plants home to examine the following day.)

Ask:

What do your model plants look like now?

Did any of your model plants dry out? Which ones?

Did any of them hold water overnight? Which ones?

What differences are there between plants that dried out and ones that kept their water?

What do you think would happen if you built an identical plant, but you didn't coat it with waxed paper? Give it a try!

What do you think would happen if you built a plant that looks different—taller, shorter, fatter, or has a different shape? If time allows, have them give it a try!

(Optional) Now that students have completed the activity, you may choose to show them the “Roots and Shoots” video. Have a short discussion in which you compare your students’ results with the outcomes for the kids in the video. What similarities and differences are there between the plants your students built and the ones the kids built? Did the model plants differ in their ability to hold and store water? If so, what might be some reasons why?

As an extension, you may want to try the Explore Some More ideas listed in Teaching Tips.

Here are suggested ways to engage students with this video and with explorations related to adaptation and to plant structures and how they function.

You may want to have students do the activity (see Activity drop-down option below) prior to watching the video. This will allow you to reinforce the concepts raised in the activity and extend your discussion by comparing your students’ results with what they see in the video. If you prefer to watch the video first, or only to watch the video, use the “Viewing the Video” suggestions below.

Viewing the Video: Use the following suggestions to guide students’ viewing of the video.

Before: Have a short discussion about plants. If you have a plant in your classroom, hold it up and ask: Can this plant get itself a glass of water when it gets thirsty? Talk about how plants get water: they have structures called roots, which take up water from the environment.

After: Have a short discussion about how the sisters in the video built their model plants, and what limitations their models might have. What materials did they use to model plant parts, such as roots, stems, and leaves? How did these materials show how these plant parts take up and store water? What are some ways in which real plants differ from these models?

Explore Some More:

Plants in the Produce Aisle Bring in an assortment of produce and herbs, such as celery stalks, lettuce leaves, artichoke petals, asparagus spears, rosemary leaves, and basil leaves. You also could bring in houseplants, such as jade, aloe, cacti, ferns, and philodendron. Give students time to explore the items.

Ask:

Which of these do you think is best at storing water? Why?

Which will lose water the quickest? Why?

Let the produce and herbs sit overnight on a plate or paper towel. The next day, ask students to examine them. How did they change? You also might ask students if they can figure out which part of the plant—root, stem, leaf, or flower—each piece of produce is. They might be surprised to learn that the nodules on a head of broccoli are actually flower buds!

Explore Roots Remove a small potted plant from its container and shake off the soil. Show students the roots.

Ask:

What are these?

What do they do? They take up water and nutrients from the soil.

How do their roots help plants survive in different ecosystems? By growing deep into the ground to reach water; by branching out close to the surface of the ground to absorb water as it begins to soak into the soil

Encourage students to think about how the plants they see every day—grass, trees along the sidewalk, weeds growing along the roads—get the water they need. Roots often extend as far out as a tree's canopy. Take some chalk and mark out how far the roots of a tree might extend under the sidewalk.